Headlamps



G. LINDAE HEADLAMPS March 26, 1963 2 Sheets-Sheet 1 Filed Feb. 10. 1959 INVENTOIQ W G. LINDAE HEADLAMPS March 26, 1963 2 Sheets-Sheet 2 Filed Feb. 10, 1959 INVENTOR 3,683,315 HEADLAMPS Gerhard Lindae, Feiibacla, near Stuttgart, Germany, as- Signor to Robert Bosch G.m.b.H., Stuttgart, Germany Fried Feb. it), 1955 cr. No. 7?2,389 Claims priority, application Germany Feb. 13, 1958 4- Claims. (Cl. 313-117) The present invention relates to headlamps which are adapted to be used with automobiles or the like.

One of the objects of the present invention is to provide a headlamp of this type which will have a downwardly directed low-beam having on the side of the oncoming traflic a well-defined shadow area.

Another object of the present invention is to provide a headlamp of the above type with a screen which will cooperate with a low-beam filament and reflector of the headlamp to provide a shadow zone directed toward the oncoming traffic without appreciably diminishing the efliciency of the headlamp.

A further object of the present invention is to provide a headlamp which will reliably accomplish the above objects while at the same time composed of simple rugged elements which are capable of operating over a long period of time without maintenance.

With the above objects in view the present invention includes in a headlamp a reflector having an optical axis and a low-beam filament in the reflector extending parallel to the optical axis. A relatively narrow elongated opaque strip extends, in accordance with the present invention, parallel to the low-beam filament at substantially the same elevation as the same to provide a light distribution which has a well-defined shadow area directed toward the oncoming traflic.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

FIG. 1 is a perspective view of the structure of the invention with the reflector of the lamp omitted for the sake of clarity;

FIG. 2 is a diagram showing the light distribution pro vided by the structure of the invention;

FIG. 3 is a perspective view showing the structure of FIG. 1 in a headlamp which is fr-agmentarily illustrated,

FIG. 3 also showing a screen used to determine the light distribution pattern; and

FIG. 4 is a transverse sectional view taken along line 4-4 of FIG. 1 in the direction of the arrows.

Referring to FIGS. 1 and 3 it will be seen that the lamp 1 of the invention includes a conventional reflector 10 and connecting conductors 3-5 extending into the interior of the reflector and being substantially parallel to the optical axis 0 of the reflector. The connecting conductors 3 and 4 are electrically connected with and carry a highbeam filament coil 7 which is curved as indicated in FIG. 1 and which is located about the focal point or focus of the reflector. This construction provides a highbeam having very little stray light and used on free roads as long as there is no oncoming traffic. The direction of Patented Mar. 26, i953 travel of the vehicle carrying the lamp is shown by the arrow I in FIG. 1.

The low-beam is provided by the coiled filament 8 located in the reflector forwardly of its focal point and extending substantially parallel to the optical axis. The ends of the filament 8 are fixed to the connecting conductors 3 and 5 as by being welded thereto so that filament 8 is electrically connected with and carried by the connecting conductors 3 and 5.

The connecting conductor 3 simultaneously serve as a support for a small narrow elongated opaque band or strip 9 which extends substantially parallel to and is located beside the filament 8 at substantially the same elevation as the filament 8. At its end which is nearest to the high beam filament 7 and the rear end of the reflector 10 the strip 9 is curved toward and extends across the optical axis so that the strip has at its rear end a portion extending angularly from the remainder of the strip 9 through a vertical plane in which the optical axis is located when the lamp is mounted on a vehicle, the filament 8 and strip 9 being located on opposite sides of this vertical plane at an elevation somewhat higher than the optical axis. The strip 9 is of arcuate cross section, as shown most clearly in FIG. 4, and has a concave surface directed toward the filament 8. This strip 9 may be made, for example, of sheet steel which may be nickelled and is fixed to the connecting conductor 3 as by being Welded thereto.

The above-described structure of the invention is mounted with the parts in the position illustrated so that the filament 8 is located on the same side of the optical axis as the oncoming trafiic while the screen member 9 is on the same side of the optical axis as the edge of the road distant from the oncoming traffic, so that the optical axis is between the oncoming trafiic and the latter edge of the road. When the light from the lamp of the invention is projected onto a screen such as the screen 11 shown in FIG. 3, the lamp of the invention will provide the light distribution indicated in FIG. 2, when the low-beam filament S is energized. The optical axis OO intersects the screen at the point 0. The light distribution is shown with respect to the horizontal axis A-A and the vertical axis BB which intersect each other at the point 0. The curves a-k connect points of equal light intensity which, starting from the brightest area surrounded by the curve a become of gradually less light intensity toward the outermost curve k. The screening strip 9 provides .in cooperation with filament 8 and reflector 10 a substantially sector-shaped well defined shadow zone extending between the substantially horizontal limit m between the light and dark areas in a clockwise direction, as viewed in FIG. 2, to approximately 30 around the point 0 to the boundary n between the light and dark areas. The horizontal boundary In between the light and dark areas is located slightly beneath the horizontal axis A-A.

The location of the filament 8 somewhat higher than the optical axis will cause the low-beam to be directed downwardly.

As may be seen from FIG. 3, the strip 9 will have no influence on light directed from the left side of the reflector, as viewed in FIG. 3, toward the screen 11 on the right side of the point 0, while it will interrupt light passing from the filament 8 toward the right side of the reflector, as viewed in FIG. 3, so as to produce the light distribution pattern illustrated in FIG. 2.

The small strip 9 has substantially no influence on the light distribution provided when the high-beam filament 7 is energized.

It will be noted from FIG. 2 that the lamp of the invention provides a light distribution extending all the way across the road on which the vehicle is travelling in cluding the outer edge of the road while the region of weakest relatively dim light between the lines m and n of'FIG. 2 is directed towardthe oncoming traffic-so as to eliminate glare. Inasmuch as only a relatively small sector of light is dimmed by the strip Qbalmostfull use 'of thelight is obtained. Thus, when the low-beamfilament -Since the lamp of the invention provides a highly eflicient light distribution when thelow-beam filament-is energized, it is unnecessary to use in the lamp of the invention lens elements heretofore necessary to provide the desiredilight distribution and undesirably influencing the focussing and range of the high-beam. Thus, with the structure of the invention a sharper focussing and substantiallygreater range of the high-beam is provided, as compared to conventional headlamps. When the low-beam filament of the lamp of the invention is energized, the drivers of vehicles in the oncoming traffic are protectedagainstrglare. The greater-brightnessof the low-beam light beyond the region of dim light directed toward the oncoming traffic is not-only ofadvantage to the driver of the vehicleprovidedwith lamps constructed according to the invention, but also of advantage to the drivers'of the vehicles in theoncoming trafiic since this lightsharplyorients the side of the road opposite from the oncoming trafiic and provides therefore greater safety when vehicles travelling in-opposite directions pass each other;

Of course, the above-described structure of: the-invention applies to those countries where vehicles keep to the right of the road so that theoncoming traffic is on the left. In those countrieswhere vehicles'are required to keep to the left side of theroad, so that the oncoming traflic is onthe right, the filament 8 would be on the right side of the optical axis andthe-screening strip 9. on the left side of the optical axis. 7 i

It, will be understood that each of the elements de scribed above, or -two or more together, may also find a useful application in other typesof lamps difieringfrom the types described above. r r r While-the invention has been illustrated and described as embodied in headlamps,- it isnot intended to be limited to the-details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Withoutfurther analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting .features that, from the standpoint of prior art, fairly constituteessential charac-' teristics of the generic or specific aspects of this invention and,therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims. t a

What is claimed as new and desired to be secured by Letters Patent-is: a

- i. In a headlamp for an automobile or the like, in combination, a reflector having a focus andan optical axis; a high beam filament located in the region of said foc'usya lowabeam filamentlocated in the reflector ata' higher. elevation than said focus and high beam filament, when the reflector is mounted on the automobile, and laterallyon one side ofthe axis extending substantially parallel thereto; and an elongated opaque strip having a length considerably greater than its width and being curved transverse to its elongation, said strip being lo cated in the reflector at the elevation of said low beam filament, on the opposite side of said axis and concave toward said low beam filament, said strip having one portion extending substantially parallel to said loW beam filament and another portion extending from one end of said one portion nearer to said focus than the other end thereof transverse to said low beam filament toward said axis.-

2. In a headlamp for an automobile or the like, in combination, a reflector having a focus and an optical axis; a high beam filament located in the region of said focus; a low beam filament located in the reflector at a higher elevation than said high beam filament, when the reflector ismounted on the automobile, and laterally on one side of said axis and extending substantially parallel thereto; and an elongated opaque strip having a length considerably greater than its width and being curved transverse to its elongation with its concave side directed to ward said low beam filament, said strip being located in the reflector at the elevation of said low beam filament, on the opposite side of said axis, said strip having one portion extending substantially parallel to said low beam filament and another portion extending curved substantially parallel to the portion of the reflector located rearwardly of said other strip portion from one end of said one portion nearer tosaid focus than the other end thereof toward said axis.

3. In a headlamp for an automobile or the like, in combination; a reflector having a focus and an optical axis; a high beam filament located in the region of said focus, an elongated low beam filament located insaid reflector and being wound in a spiral of selected diameter about an axis extending substantially parallel to said optical axis to one side of the latter and said axis of said low beam filament spiral being located, when said reflector is mounted at the automobile, at an elevation higher than that of said optical axis of said reflector; and an elongated'opaque strip having a width at least equal to the diameter of saidlow beam filament spiral and alength considerably greater than said diameter and being curved in a direction transverse to its-lengths, said strip extending symmetrically to a horizontal plane passing through the said axis offsaid low beam filament spiral and substantially normal thereto on the opposite side of said optical axis with its concave side directed towardsa-id low beam filament, said strip having-one portion extending substantially parallel to said low beam filament and another portion extending curved substantially para'llel' to the portion of the reflector located of said other strip portion from oneend of said one portion nearer to said focus than the other end thereof toward said axis.

4. In a head-lamp for an automobile or the like, in combination, a'refiector having a focus andan optical axis; a high beam filament located in the region of said focus; a low beam filament located in the reflector at a higher elevation than said'high beam filament, when the reflector is mounted on the automobile, and laterally onone side of said axis and extending substantially parallel thereto; a pair of connecting conductors extending into said reflector, connected electrically to and supporting said low beam filament; and an elongated opaque strip having a length considerably greater than its Width andbeing curved transverse to its elongation with its concave side directed toward said low beam filament, saidstrip being carried by one of said connecting conductors in thereflector at the elevation of said low beam filament, on the opposite side of said axis, said strip having one portion extending substantially parallel to said low 'beam filament and another portion extending curved substantially parallel to the portion of the reflector. located rearwardly of said other strip port-ion from one end of said one portion nearer to said focus than the other end thereof toward said axis.

References Cited in the file of this patent UNITED STATES PATENTS 5 1,716,048 Graves June 4, 1929 1,793,398 Harnberger Feb. 17, 1931 1,923,181 Albers Aug. 22, 1933 6 Honing June 25, 1935 Birdseye Jan. 17, 1939 Hayden Aug. 29, 1939 Meese Oct. 28, 1958 Verbeek Jan. 13, 1959 FOREIGN PATENTS Australia Mar. 11, 1954 Australia Aug. 18, 1955 

1. IN A HEADLAMP FOR AN AUTOMOBILE OR THE LIKE, IN COMBINATION, A REFLECTOR HAVING A FOCUS AND AN OPTICAL AXIS; A HIGH BEAM FILAMENT LOCATED IN THE REGION OF SAID FOCUS; A LOW BEAM FILAMENT LOCATED IN THE REFLECTOR AT A HIGHER ELEVATION THAN SAID FOCUS AND HIGH BEAM FILAMENT, WHEN THE REFLECTOR IS MOUNTED ON THE AUTOMOBILE, AND LATERALLY ON ONE SIDE OF THE AXIS EXTENDING SUBSTANTIALLY PARALLEL THERETO; AND AN ELONGATED OPAQUE STRIP HAVING A LENGTH CONSIDERABLY GREATER THAN ITS WIDTH AND BEING CURVED TRANSVERSE TO ITS ELONGATION, SAID STRIP BEING LO- 